1. Field of the Invention
The present invention provides medical diagnostic methods for detecting and typing HPV. The method utilizes PCR, a DNA amplification technique widely used in the fields of molecular biology and genetic engineering. The method can also be used to generate information concerning previously known strains of HPV and consequently has applications in the field of virology
2. Description of Related Disclosures
Papillomaviruses have been linked to widespread, serious human diseases, especially carcinomas of the genital and oral mucosa. And although genital HPV infection is associated with cancer primarily in women, recent evidence suggests that HPV may play a role in the development of prostate cancer in man. Broker et al., 1986, Cancer Cells 4:17-36, review the molecular, cellular, and clinical aspects of the papillomaviruses and the relationship of HPVs to cancer. HPV types 6, 11, 16, 18, and 33 are known HPV types in the human population, and Broker et al., 1986, Cancer Cells 4:589-594, disclose that HPV types 6, 11, and 18 share significant homology at the DNA level, particularly at the L1 open reading frame.
Identification and typing of HPV is quite important, because different types of HPV pose different risks to the affected individuals. For instance, HPV16 and HPV18 have been more consistently identified in higher grades of cervical dysplasia and carcinoma than other HPV types. Webb et al., December 1987, J. Inf. Disease 156(6):912-919, report a method for detecting HPV DNA types that utilizes a reverse-blotting procedure. The procedure involved forming a membrane to which genomic DNA from four different HPV types was bound and then hybridizing labelled DNA from a biological sample to the DNA bound to the membrane. Caussey et al., February 1988, J. Clin. Microbiol. 26(2):236-243 describe similar HPV detection methods.
Shibata et al., January 1988, J. Exp. Med. 167:225-230, disclose the use of PCR to amplify and detect the presence of HPV16 and HPV18 DNA. U.S. Pat. Nos. 4,683,195 and 4,683,202 disclose PCR and the use of PCR to detect the presence or absence of nucleic acid sequence in a sample. European Patent Publication Nos. 229,701 and 269,445 disclose the use of PCR to amplify and detect DNA sequences associated with a wide variety of viruses, including the AIDS virus, HTL V I, and HTL V II.
Maitland et al., May 1988, Seventh International Papillomavirus Workshop, Abstract, p. 5, report the use of PCR to detect HPV16 in oral and cervical biopsies. In addition, Campione-Piccardo et al., May 1988, Seventh International Papillomavirus Workshop, Abstract, p. 19, report the use of a mixture of primers for the specific amplification by PCR of HPV sequences regardless of type. A number of other researchers disclosed the use of PCR to amplify and detect HPV sequences at the Seventh International Papillomavirus Workshop.
Instruments for performing automated PCR are described in pending U.S. patent application Ser. No. 899,061, filed Aug. 22, 1986, which is a continuation-in-part of Ser. No. 833,368, filed Feb. 25, 1986, now abandoned. The preferred polymerase enzyme for use with PCR is Taq polymerase, isolated from Thermus aquaticus. Methods for purifying Taq polymerase and for the recombinant expression of the enzyme are disclosed in Ser. No. 143,441, filed Jan. 12, 1988, now abandoned, which is a continuation-in-part of Ser. No. 063,509, filed Jun. 17, 1987, which issued as U.S. Pat. No. 4,889,818, which is a continuation-in-part of Ser. No. 899,241, filed Aug. 22, 1986, now abandoned. The disclosures of these U.S. patents and patent applications are incorporated herein by reference.
Despite the use of PCR to amplify and detect HPV sequences, there still remains a need for a simple and rapid method for both detecting and typing HPV in a biological sample. The person invention provides a method that meets that need.